Southern Pacific Railroad The Southern Pacific (or Espee from the railroad initials) was an American Railroad classes#Class I, Class I Rail transport, railroad network that existed from 1865 to 1996 and operated largely in the Western United States. The system was oper ...

's AC-12 class of simple

articulated An articulated vehicle is a vehicle which has a permanent or semi-permanent coupling in its construction. This coupling works as a large pivot joint, allowing it to bend and turn more sharply. There are many kinds, from heavy equipment to buse ...

4-8-8-2 Under the Whyte notation for the classification of steam locomotives, a 4-8-8-2 is a locomotive with four leading wheels, two sets of eight driving wheels, and a two-wheel trailing truck. Other equivalent classifications are: UIC classificat ...

cab forward The term cab forward refers to various Rail transport, rail and road vehicle designs that place the driver's compartment substantially farther towards the front than is common practice. Rail locomotives In steam locomotive design, a cab-forwa ...

steam locomotive A steam locomotive is a locomotive that provides the force to move itself and other vehicles by means of the expansion of steam. It is fuelled by burning combustible material (usually coal, Fuel oil, oil or, rarely, Wood fuel, wood) to heat ...

s was the last class of steam locomotives ordered by Southern Pacific. They were built by

Baldwin Locomotive Works The Baldwin Locomotive Works (BLW) was an American manufacturer of railway locomotives from 1825 to 1951. Originally located in Philadelphia, Pennsylvania, it moved to nearby Eddystone, Pennsylvania, Eddystone in the early 20th century. The com ...

during

World War II World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the wo ...

, with the first, number 4275, entering service on October 27, 1943, and the last, 4294, on March 19, 1944. Each locomotive was effectively a conventional 2-8-8-4 locomotive running in reverse, the tender being coupled at the smokebox end of the locomotive. This was made possible by the use of oil-firing. The distinct features of these locomotives include: a streamlined front with white band, an air horn on the front, a streamlined pilot, a SP 12 wheel box tender, and air compressors mounted on the smokebox. Southern Pacific used these locomotives all over its system, but they were extremely famous for working on Donner Pass & Cascade Summit. SP used the AC-12s for a little over a decade with the first retirements occurring on April 5, 1955, and the last on September 24, 1958. Only one AC-12, SP 4294, has survived into preservation and is now on display at the

California State Railroad Museum The California State Railroad Museum is a museum in the California State Parks system that interprets the role of railroads in the Western U.S. It is located in Old Sacramento State Historic Park at 111 I Street, Sacramento, California. Featu ...

References

* {{SP AC class locomotives AC-12 4-8-8-2 locomotives Baldwin locomotives Simple articulated locomotives Railway locomotives introduced in 1943 Steam locomotives of the United States Standard-gauge locomotives of the United States Freight locomotives Cab_forward_steam_locomotives